This study evaluates the safety, tolerability, and the effect of an experimental drug called AC2993 on blood glucose in people with type 2 diabetes. AC2993 is a man made substance that has certain actions that are similar to hormone that is normally found in people called glucagon-like peptide-1. It is suggested that AC2993 may reduce the after meal increases of glucose in people with type 2 diabetes mellitus in a similar manner to glucagon-like peptide-1. This study is designed to evaluate the safety and the effect of multiple doses of AC2993 on blood glucose in people with type 2 diabetes mellitus.